The present invention relates generally to an agricultural primary tillage implement, and more particularly to such an implement featuring a row cleaner assembly attached in front of the shank. As used herein, primary tillage means deep soil plowing, in an approximate range of 8 to 14-inches or greater. Secondary tillage may be in an approximate range of 3 to 6-inches.
Primary tillage is, of course, not in and of itself new, having started with the first plow to cut land. Improvements in tillage practices are generally slow to reach acceptance and almost always show themselves as small steps. Tillage implements providing both secondary and primary tillage in a single pass using disks and chisel points are also not generically new, as shown by U.S. Pat. Nos. 4,245,706; 4,403,662; and 4,538,689. These machines, however, do not create the best possible seedbed, i.e., do not create the soil conditions that best promote seed germination and plant growth.
During the late 1970""s, before the machine shown in U.S. Pat. No. 4,403,662 became available, primary tillage was accomplished principally with moldboard plows. The moldboard plow leaves large slabs and chunks of soil that tend to break down during the freeze and thaw cycles of winter, but this type of plowing requires substantial working of the soil in the spring in order to level the field and prepare it for planting of the next crop. Moreover, moldboard plowing is not an effective remedy for soil erosion, and actually has a tendency to exacerbate this problem.
In recent years, farmers have recognized the long-term detrimental effects to the land characteristic of traditional farming techniques, and have been searching and experimenting for ways to decrease soil and wind erosion. The use of a large disk assembly in front of a chisel plow on a parabolic shank has gone a long way toward accomplishing these objectives and also breaks up the hard plow pan (or xe2x80x9csolexe2x80x9d) that is created at the particular depth at which the plow is set to operate, caused by repeated tillage at the same depth over the years. The parabolic shank and winged point do reduce soil erosion, but this practice also may create large chunks of soil, and usually requires substantial spring soil working to prepare an adequate seedbed for planting.
During the 1970""s, the cutter chisel was widely used. It consisted of a chisel plow with a row of coulters to cut the residue ahead of two rows of staggered shanks, generally on thirty-inch centers. These shanks had a four-inch twisted point attached to perform the primary tillage. The tip of the point was at approximately a 45xc2x0 angle to the horizontal, sloping downwardly and forwardly from the shank. The worked soil followed the curvature of the generally C-shaped shank that was attached to the chisel plow and was twisted in order to provide a moldboard-type turning action. A C-shaped shank, of the type described, is shown in U.S. Pat. No. 4,403,662.
For early cutter chisel plows, there was a net lateral movement of soil. A machine with, for example, eleven shanks would be equipped with five right-hand and six left-hand twisted points. The result was that a wide groove and a large berm were left after a pass. The machine as shown in U.S. Pat. No. 4,403,662 was an improvement because it left a smaller groove and not as large a berm by using fore-and-aft sets of disks and an improved point.
In U.S. Pat. No. 4,538,689, there is disclosed a winged point mounted on a parabolic shank. That winged point, in the combination shown, creates a large, rough surface similar to the surface of the moldboard plow used during the late 1970""s and early 1980""s. The wings on these points are set at a soil lift, twist and roll angle of approximately 30xc2x0. This lift angle was conventional at the time, but it is an aggressive angle that causes the wings to lift the soil abruptly. In some soils, particularly more compacted soils, the combination of an aggressive lift angle on the wings of the point, together with a parabolic shank, that is designed to lift and heave soil, lifted larger soil chunks and threw them out of the paths of the chisel plow and away from cooperating disks, making it difficult to create a level soil surface after a pass of the machine.
During the 1980""s, researchers and farmers began to better understand the seedbed requirements for improved germination, emergence and growth. They also began to better understand the desirability of using less tillage to improve soil conservation and erosion prevention. The furrows left by the chisel shanks had to be filled with the berms that were created between each shank. In order to fill these furrows behind large parabolic shanks, smaller shanks were placed to run shallower and were located midway between the larger chisel shanks. This resulted in smaller grooves on reduced centers. With the development of the disk leveler shown in U.S. Pat. No. 5,080,178, the furrows behind the shanks were substantially filled without leaving sizeable grooves after the shanks had passed, thus improving the level or xe2x80x9csmoothnessxe2x80x9d of the surface.
As today""s farming operators are trying to combine multiple tillage operations into fewer passes, while maintaining or improving yields and reducing erosion, Crop Residue Management (CRM) has become a well-accepted practice. CRM is a year-round system beginning with the selection of crops that produce sufficient quantities of residue and may include the use of cover crops after low residue-producing crops. CRM includes all field operations that affect residue amounts, orientation and distribution throughout the seasonal period requiring protection. Tillage systems included, among others, under CRM are no-till, ridge-till, mulch-till and reduced-till. A change in tillage and planting operations to increase crop residues on the soil surface has been shown to produce crop yields generally equal to or higher than those produced by systems that leave little or no residue on the field after planting. However, more residue means fewer trips across the field, which translates to lower fuel bills, less soil compaction, and less wear and tear on equipment.
The objective of CRM is to accomplish the necessary primary tillage and prepare the best seedbed possible with a minimum number of equipment passes while maintaining a minimum disturbance of the crop residue. The present invention is an improvement that helps produce a better seedbed.
It is an object of the instant invention to provide an agricultural primary tillage implement that is designed to perform complete tillage of the soil in a single pass while leaving a raised-berm seedbed with reduced residue and smaller clod sizes of soil in line with the shank swath.
It is another object of the instant invention to provide an agricultural primary tillage implement that supports the Crop Residue Management approach to farming.
It is a further object of the instant invention to provide an agricultural primary tillage implement employing a row cleaner assembly in front of the shank.
It is a still further object of the instant invention to provide an agricultural primary tillage implement that prepares an improved seedbed.
It is an even still further object of the instant invention to provide an agricultural primary tillage implement that prepares a seedbed with better seed-to-soil contact and cleaner soil for the planter to run in, preventing planter plugging and uneven seed planting depth.
These and other objects are obtained by providing an agricultural primary tillage implement with a row cleaner assembly attached in front of the shank. That row cleaner is adjustable fore-and-aft for optimum clearance between the shank and a leading soil preparation apparatus to maximize clearance for residue movement. The row cleaner is also adjustable for depth. The row cleaner assembly reduces the amount of residue in line with the shank path (row) and creates smaller clod sizes of soil in line with the shank swath, resulting in a better seedbed and faster warm up in the spring, enabling the planter to run in cleaner soil, preventing planter plugging and uneven seed planting depth as well as resulting in better seed-to soil-contact.